/Engine/Source/Runtime/Engine/Classes/Kismet/GameplayStatics.h
Try and find the UV for a collision impact. Note this ONLY works if 'Support UV From Hit Results' is enabled in Physics Settings.
static bool FindCollisionUV ( const struct [FHitResult](API\Runtime\Engine\Engine\FHitResult) & Hit, int32 UVChannel, FVector2D & UV )